Power-divided transmission



c. 4. BOCK 2,158,320

' POWER-DIVIDED TRANSMISSION May 16, 1939.

IS Sheets-Sheet 1 Filed Oct. 7, 1937 ""lllliw lhwentor 4 a /1 y (Ittornegs y 1939- Q J. BOCHK 2,158,320

, POWER-DIVIDED TRANSMISSION Fi led Oct. '7, 1957 v 3 Sheets-Sheet 2 ammegs 3nnentor May 16, 1939. QCK 2,158,320

POWER-DIVIDED TRANSMIS S ION Filed Oc t. v, 1957 r 5 Sheets-Sheet 5 lnnentor 602/ flock Bg W M Gttomegf Patented May 16, 1939 UNITED STATES PATENT OFFICE rowna-mvman rmsmssron Carl J. Bock, Birmingham, Mich assignor to Yellow Truck 8; Coach Manufacturing Company, Pontiac, Mich, a corporation of Maine Application October '1, 1937, Serial No. 167,686

'IClaims.

tremes of light load high speed operation on good roads and heavy load low speed operation on very bad roads, the latter requiring more pulling power. a

An object of the invention is to provide mechanism for the transmission of power from a common source to several driving axles incorporating high and low speed ranges with optional differential drive. The intention is that the device be auxiliary to the conventional. change speed mechanism of the motor vehicle, although for some types of work it could serve alone as the variable speed mechanism. For the more unfavorable driving condition, as for example, where one or more sets of road wheels ride in soft earth, the drive transmitting mechanism can be set to lock out the differential action and divide the power equally among the axles. Otherwise differential drive is employed to reduce scrubbing and rapid wear of the tire tread caused by differences in road contour and tire radii.

For a more complete understanding, reference may be made to. the accompanying drawings wherein Figure 1 is a plan view showing a portion of a motor vehicle and the operating connections for three drive axles; Figure 2 is a horizontal sectional view through the auxiliary gear box; Fig ure 3 shows the control rod and shifter forks through which drive relations are established; Flgure4 is a detail perspective view of the hand shift lever and its mounting, and Figures 5 and 6 are sectional views showing modified forms of the gearing mechanism.

The road wheel and axle assemblies to be used can be of any suitable construction and the drive can be through either four or six wheels. In the four wheel drive combination wherein two drive axles each have two wheels, according to the preferred embodiment, power is transmitted differentially between the axles in either high or low speed settings or without differential action in low speed setting. For the purpose of disclosure the six wheel driveis illustrated and in this arrangement all six wheels are driven only to take care of the more difllcult situations with the transmission set in the low speed range and the differential cut out of action. Under more favorable conditions power is transmitted through the differential to only four wheels in either high or low speed ranges.

The customary arrangement of the axles for a six wheel vehicle is shown in Figure 1 wherein a steering drive axle I is located at the front and a pair of tandem drive axles'2 and 3 are located at the rear. The chassis frame 4 is supported upon the axles through any well known type of spring suspension and serves .to mount the body and engine in the conventional manner.

The power plant, omitted from the drawings for the sake of simplicity, may be considered as comprising the usual engine, clutch and change speed gear box, the output shaft of which is joined to the input shaft 5 of the auxiliary gear box 6 enclosing the mechanism through which power is divided between and drives the spaced output shafts I, 8 and 9 operably connected by propeller shafts with the differential drive units of the axle assemblies I, 2 and 3, respectively.

Referring now to Figure 2, it will be seen that the several shafts 5, I, 8 and 9 are rotatably mounted at opposite ends in suitable bearings in the front and rear walls of the gear box 6 and carry intermeshing gears for the division and transmission of power in selected relations: The gearing assembly on the input shaft 5 includes a pair of spaced gear elements It and H, the adjacent faces of which carry bevel gear teeth l2 and I3, respectively, engaging with differential tooth pinions H on the spider l5 splined to the input shaft 5, whereby the elements I0 and H may be driven differentially from the input shaft. To lock out the differential action the opposite end of the element In is provided with external clutch teeth It for engagement with internal clutch teeth I! of a slider l8 splined to the shaft 5 and which engagement causes the slider l8, the element ill, the spider l5 and the element II to rotate as a unit.

Both gear elements It and H are geared for drive connection with each of the output shafts 8 and 9, the arrangement being such that either of two speed ratios may be had. The low speed gear IS on the element It and the low speed gear 20 on the element II are identical and the high speed gears 2| and 22 on the respective elements are also identical. A gear 23 rotatably mounted on the shaft 9 meshes with the low speed gear l9 and a similar gear 24 rotatable on the output shaft 8 meshes with the other low speed gear 20. The shaft 8 also has rotatably mounted thereon a gear 25 meshing with the high speed gear 2| and a similar gear 26 meshing with the high. speed gear 22 is rotatable on the shaft 9. splined on the shaft 3 between the gears 23 and 28 is a slidable coupler 21 provided at opposite ends with external clutch teeth 28 and 23 selectively engageable with internal clutch teeth 38 and 3| on the respective gears. A like coupler 32 is splined on the shaft 8 and carries external clutch teeth 33 at one end for engagement with the internal clutch teeth 34 on the gear 24 and external clutch teeth 35 at its opposite end for coupling with the internal teeth 35 on the gear 25.

For operating the output shaft 1 the driving gear 31 is keyed or otherwise fixed to the shaft 9 and meshes with a gear 38 in a ratio of one to one. This gear 38 which is rotatably mounted on the shaft 1 carries internal clutch teeth 33 for coupling with the external teeth 40 of the slidable collar 4| splined on the shaft 1.

It will be apparent that through the several clutching devices various combinations of drive relations may be established. If the vehicle is to be equipped with but two drive axles the shaft 1 and its gear train would be omitted and should it be desired to place the unit between a pair of drive axles located at opposite ends of the vehicle one of the shafts 8 and 9 would be extended rearwardly and the other forwardly. At the moment the intention is to arrange the controls so that any one of three drive relations may be effected.

In one setting only the 'two rear axles are driven through the differential in. high speed gearing; in another setting the rear axles only are driven through the low speed gearing with the difierential free, and in the remaining setting all three axles are driven through the low speed gearing with the differential locked out.

Figure 2 illustrates the parts for high speed drive through the differential to the rear axles onlyfthe slidable clutches I8 and 4| being released and the clutches 21 and 32 coupling the gear 26 with the output shaft 9 and the gear 25 with the output shaft 8. The transmission of power from the input shaft 5is divided through the differential gearing l2, I3 and I4, part going from the gearing element I8 through gears 2| and 25 to the output shaft 8 and the remainder from the gearing element through the gears 22 and 26 to the output shaft 9. For low speed drive to the rear axles through the differential the clutches I8 and 4| are left in released position and both sliders 21 and 32 are shifted into coupling relation with the gears 23 and 24, respectively, the power then passing through the differential and partly through the gears I9 and 23 to the shaft 9 and partly through the gears 20 and 24 to the shaft 8. For drive in low gear with the differential locked, the gears 23 and 24 are coupled to their respective shafts and the slider I8 is shifted to engage the clutch teeth I8 and I1 in which case the elements 10 and I I and the differential mechanism rotate together driving the shafts 8 and 3 through the gears 24 and 23. Concurrently with the setting of the clutch 18 the clutch 4| may be'shifted to couple the gear 38 with the output shaft 1 through the teeth 39 and 40 so that the shaft 1 is driven through the gear 31 at the same rate of speed as are the shafts 8 and 3.

For positioning the parts in the several driving relations mentioned, hand controlled shifter forks may be employed. Thus the sliding clutches 21 and 32 are each provided with annular grooves 42 and 43 to receive' shifter forks 44 and 45 mounted on the slidable rods 43 and 41.

. with annular grooves 48 and. 50 to receive the shifter forks 5| and 52 mounted on the same slide rod 53 so that the clutches I8 and 4| are moved concurrently in the same direction for the coupling and uncoupling operations.

For moving the shift rods they are extended to the drivers position, the extension in the case of the rod 53 being in the form of a rocking leven 54 and a rod 55 and both extensions are provided with notches adapted for selective engagement with the head 56 on a hand shift lever 58. This hand lever 58 is mounted for rocking and transverse sliding movement on a pin 59 in a mounting tower 50 and extends through a Z-shaped slot 5| in the top of the tower which guides the hand lever to any one of its three gear setting positions. For setting the parts in the relation shown in Figure 2 the hand lever is moved from the intermediate position shown in Figure 4 to one side and then moved forward in the slot 6|.

The side movement of the lever brings the head 58 into engagement with the notch of the forward end of the rod 43 and the subsequent rocking movement of the lever slides the rod toward the right as shown in Figure 3 and through the rock lever 48 slides the rod 41 toward the left. This positions the parts for drive through the differential to the rear axles in the high speed range. When the lever is set to the intermediate position as in Figure 4 the rods 43 and 41 are restored andare positioned so that the gear 23 is coupled to the shaft 9 and the gear 24 is coupled to the shaft8 which gives the low speed drive through the differential to the pair of rear axles. The rod 55 is shifted by first moving the hand lever 58 transversely and then back in the slot 6 I, pulling the rod 55 toward the left in Figure 3 and through the rock lever 54, shifting the rod 53 toward the right, which causes the clutches I8 and 4| to be moved simultaneously to coupling position thereby locking out-the differential and driving all three axles through the low speed gears.

For a more compact arrangement of the gearing and to enable the use of an auxiliary adapter as optional equipment for converting a four wheel drive mechanism into a six wheel drive arrangement, the structure as shown in Figure 5 has been provided. In this instance the arrangement of the input and output shafts and associated gearing is substantially that of Figure 2 except that the ger 31 has been omitted and is replaced by a spacer collar 62. The casing 6a in this instance has an opening at one side for attachment of the casing 53 forming a part of the optional assembly. and in which is mounted on suitable bearings the output shaft 1a for the front axle. This shaft has rotatably mounted thereon a gear 64' to mesh with the low speed driven gear 23 of the output shaft 9. The gear 64 carries internal clutch teeth to engage with the external clutch teeth of the slider 65 splined on the shaft 1a and having an annular groove 65 to receive a shifter fork 61 on a slide rod 55a. This slide rod 55a may be formed as an extension of the shifter rod 55 previously referred to and which is connected by the rock lever 54 with the slide rod 53. In this instance as the rod 53 is moved toward the right in Figure 3to lock out the differential the rod 55 simultaneously moves toward.

the left and shifts the clutch 88 to couple the gear 84 with the output shaft la. The construction and operation is otherwise as before described.

The structure in Figure 6 also embodies as optional equipment a drive for the front axle in addition to the drive for tandem rear axles. In

this instance, however, the gearing is such that the threespeed settings involve high and low ranges, both with the differential locked and ad- .ditionally a high range with the diflerential free.

With three driving axles, all three axles may be driven with the difierential locked in either high or low range, the front axle being cut out only in the high range with the drive through the differential. Referring more particularly to the structure shown in Figure, 6 the input shaft is shown at 18, the output shaft for the front axle at H and the output shafts for the rear axles at 12 and 13. Each of these shafts is mounted at opposite ends in suitable bearings in the housings l4 and 15. The input shaft I8 has a differential spider l8 splined thereon with differential pinions engaging side gears 18 and 18 on a pair of high speed gears 88 and 8|: The gear 8| is in mesh with a gear 82 keyed orotherwise fixed on the output shaft 13 while the gear 88 meshes with a gear 88 rotatably mounted on the output shaft 12 and adapted to be clutched to the shaft by a slider 84 splined on the shaft. The gear 8| is also in mesh with a gear 85.which is formed integral with a gear 88 meshing with a gear 8'! rotatably mounted on the input shaft 18. A slider 88 splined on the shaft 18 is adapted to couple with clutch teeth formed on the gear 81 and a slider 88 splined on the output shaft 12 couples the shaft with the integrally formed gears 85 and 88. The gear 85 is also in drive engagement with a gear 88 rotatably mounted on the output shaft II and adapted to be coupled thereto through a sliding clutch 8| splined on the shaft.

Each of the clutches 84, 89, 88 and 8| is provided with an annular groove for engagement with a shifter fork for setting the parts in various drive relations. The several shifter forks and control rods are shown bybroken lines. That which operates the clutch 8| is mounted-on a slide rod 82 connected by a rock lever 83 with the slide rod 94 which carries the shifter fork for the clutch 88 and extends forwardly to the manually controlled shift lever. The clutch 88- 84 and extends forwardly beside the rod 84 for manual actuation. The hand lever in this instance may be that shown in Figure 4 and when the lever is in the intermediate or central position as seen in Figure 4 the position of the spider 18 to both gears 88 and 8| driving the output shaft 13 through the gear 82 and the output shaft 12 through the gears 83 and 85, coupledthereto. In addition the gear drives the gear 88 which is in coupled position with the output shaft so that all three axles are driven.

In the event the hand shift lever 58 is moved forward in the slot'8l the shift rod 84 is moved rearwardly disengaging the clutch 88 from the gear 85 and simultaneously moving the rod 82 forwardly to disengage the clutch 8| from the gear 88. In this relation of parts the front axle receives no power and the drive to the tandem rear axle is in highspeed through the differential. The power then flows from the input shaft 18 through the differential mechanism, part going through the gears 8| and 82 to the output shaft '13 and the remainder through the gears 88 and 88 to the output shaft 12, the gear 85 rotating freely.

Shifting the hand lever 58 rearwardly in the slot 6| from the intermediate position causes the rod 88 to move forwardly and uncouple the clutch 84 between gear 83 and output shaft i2 shaft 12 through the clutch 88, the output shaft |l through the gears 85 and 88 and clutch 8|, and driving the output shaft 18 through the gears 8| and 82, the differential action being cut out by the disengagement of the clutch 84.

I claim:

1. In a variable speed power divider, an input shaft, differential drive mechanism associated therewith including a pair of side gear elements rotatably mounted on the shaft, 9. high speed gear and a low speed gear on each element, a slidable clutch selectively operable to couple one of said elements to the shaft and thereby cut out the differential action between said elements, a pair of output shafts, each having rotatably mounted thereon a high speed gear in mesh with the high speed gear of one of said elements and a low speed gear in mesh with the low speed gear of the other of said elements, and slidable clutch means on each output shaft to couple thereto the respective gears thereon.

2. In a variable speed power divider, a pair of output shafts, each having high and low speed gears rotatably mounted thereon and a slider splined thereto between said gears for clutching engagement with the respective gears, an input shaft having a pair of gear elements rotatably mounted thereon, each element having rigid therewith a high speed gear in mesh with the high speed gear on one of the output shafts and a low speed gear in meshwith the low speed gear on the other output shaft, difi'erential drive means between said elements and thei-nput shaft, and a slidableclutch splined on the input shaft for selective engagement with one of said elements to lock out the differential drive means.

3. In a variable speed power divider, a pair of output shafts, each having high speed and low speed gears rotatably mounted thereon and a slider clutch splined thereto for movement in opposite directions to couple one or the other gears to the shaft, I means for simultaneously shifting both clutches to engage either the high speed gears or the low speed gears in unison, an input shaft having a pair of gear elements rotatably mounted thereon, and each element carrying high and low speed gears meshing with mating gears on the output shafts, differential drive means between said elements and the input shaft,

' a clutch for coupling one of the elements with the input shaft, and means toengage and disengage said clutch.

4. In a variable speed power divider, an input shaft, a pair of differentially driven gears rotatably mounted on said shaft, an output shaft having rigid therewith a gear in mesh with one of said differentially driven gears, a second output shaft having rotatable thereon a pair of gears in mesh with said pair of differentially driven gears, clutch means to drive connect said rotatabiy mounted gears and the second output shaft in selected relations, a low speed gear rigid with one of said rotatably mounted gears, a driving gear meshing with said low speed gear and being rotatably mounted on the input shaft and clutch means selectively operable to couple said driving gear with the input shaft.

5. In a variable speed power divider, a pair of output shafts, each having high and low speed gears rotatably mounted thereon and clutch means for coupling said gears to the shafts, a third output shaft having rotatably mounted thereon a gear in mesh with one of the beforementioned gears and means to clutch the same to said shaft, an input shaft having a pair of differentially driven gear elements rotatably mounted thereon and each having high and low speed gears meshing with the mating gears on said output shafts and means to clutch said elements for solid drive with said input shaft.

6. In a variable speed power divider. an input shaft having a pair of differentially driven gear elements thereon, each provided with high and low speed gearing means to couple said elements for solid drive with the shaft, a pair of output shafts each having high and low speed gears meshing with the mating gearing of said-elements, selective means for coupling the respective output shafts with either the high or low speed gears thereon, a third output shaft having a gear rotatably mounted thereon, a driving gear in mesh therewith and rigidly mounted on one of the said pair of output shafts and clutch means for coupling said third output shaft with the gear carried thereby.

7. In a power divider unit, an enclosing housing, a drive shaft and a pair of driven shafts all rotatably supported within the housing in spaced parallelism, a differential spider fixed on the drive shaft and provided with differential pinions, a pair of differential side gears rotatably journaled on the drive shaft in engagement with said pinions, change speed drive transmitting mechanism between the side gears and the driven shafts, respectively, and means selectively operable to lock the differential side gears in non-rotatable relation to the drive shaft.

CARL J. BOCK. 

